Injectant stream analyzer



Aug. 29, 1967 J. D. USRY ET AL INJECTANT STREAM ANALYZER 2 Sheets-Sheet1 Filed Nov. 23, 1964 Ill i ROBERT L. WARREN JOE D. USRY INVENTORS BY WM5 ATTORNEY CURVE VALID FOR REYNOLD'S NUMBER |O Aug. 29, 1967 Filed Nov.23, 1964 J. D. USRY HAL INJECTANT STREAM ANALYZER FIG 4v STROKE 0F WIRE(INCHES) FIG 3 ROBERT L. WARREN JOE D. USRY INVENTORS W /"7, 5m

ATTORNEY United States Patent 3,338,093 INJECTANT STREAM ANALYZER Joe D.Usry, Arlington, and Robert L. Warren, Dallas, Tex., assignors toLing-Temco-Vought, Inc., Dallas, Tex., a corporation of Delaware FiledNov. 23, 1964, Ser. No. 412,962 6 Claims. (Cl. 73119) ABSTRACT OF THEDISCLOSURE This invention relates to device for measuring the momentumand solidity of fluid free streams from injection valves or the like bycausing a wire of generally triangular cross-section to transect thestream in such a manner that the stream impinges on the base of thetriangle and measuring the position of the wire and the force of thefluid impinging on the wire.

This invention relates to methods and apparatus for measuringcharacteristics of fluid streams and is particularly directed to novelmethods and apparatus for measuring characteristics of fluid streamsfrom secondary injection valves and the like. In designing or evaluatinginjector valves and the like, two basic performance objectives must beconsidered. In order to obtain maximum penetration of injectant fluidinto the nozzle gases for secondary injection, the injectant free streammus-t efi'iciently recover static pressure head after it leaves thevalve. Secondly, the injec-tant fluid stream should have a solid crosssection at all flow rates. Numerous methods and apparatus have beenproposed heretofore for measuring the extent to which these performanceobjectives are attained. However, none of the prior art methods orapparatus have been entirely satisfactory.

It has been customary previously to determine recovery of staticpressure head by measuring either the reaction thrust on the valve orthe momentum of the stream impinging on a splash plate. However, thereare decided disadvantages to either of these methods. In order toaccurately measure the reaction thrust, the injector valve must be freeof internal or external perturbations. Unfortunately, this is almostimpossible to achieve in practice because of pressure and flow forces onthe injectant supply pipe. Difiiculties are also experienced with thesplash plate method. Unless the stream solidity is extremely good,interaction of the stream droplets cause splash back and, since theangle of splash back is hard to determine, very erroneous readings areoften obtained. The standard prior art method of measuring streamsolidity has called for providing an apertured target plate upstreamfrom the splash plate and either varying the size of the aperture ormoving the target plate to shear off successive portions of the stream.However, the apparatus for accomplishing this expensive and cumbersomeand performance of the method is time consuming and, often, ofquestionable reliability.

These disadvantages of the prior art are overcome with the presentinvention and novel methods and apparatus are provided for determiningstream momentum and solidity. The apparatus of the present invention issimple in construction, rapid and accurate in operation, andinexpensive. Moreover, the method of the present invention isstraightforward and uncomplicated.

The advantages of the present invention are preferably attained byproviding a wire of wedge-shaped cross section, means supporting saidwire with the flat side thereof extending perpendicular to the flow axisof the fluid free stream to be analyzed, means for causing said wire totransect said stream, means for indicating the force 'of static pressurehead and solidity of fluid free streams.

A further object of the present invention is to provide novel methodsand apparatus for analyzing characteristics of secondary injectionvalves and the like.

A specific object of the present invention is to provide novel apparatusfor measuring characteristics of a fluid free stream, said apparatuscomprising a wire of wedgeshaped cross section, means supporting saidWire with the flat side thereof extending perpendicular to the flow axisof said stream, means for causing said wire to transect said stream,means for indicating the force of fluid impinging on said wire and meansfor indicating the position of said wire.

These and other objects and features of the present invention will beapparent from the following detailed description taken with reference tothe figures of the accompanying drawings.

In the drawings:

FIGURE 1 is a diagrammatic side view, partly in section, showingapparatus emboding the present invention for measuring characteristicsof a fluid free stream;

FIGURE 2 is a View, partly in section, taken on the line IIII of FIG. 1;

FIGURE 3 is a diagrammatic representation of the curve drawn by therecorder of FIG. 1; and

FIGURE 4 is a curve showing drag coeflicient as a function of the ratioof the dimensions of the wire and stream of FIG. 1.

In the form of the present invention chosen for purposes of illustrationin the drawing, FIG. 1 shows a valve 2 emitting a free stream of fluid 4which is to be analyzed. To analyze the stream 4, a wire 6 is tautlymounted in the ends of a yoke 8 which is formed on the free end of apiston rod 10. The-opposite end of the piston rod 10 is secured to apiston 12 which is movable within a hydraulic cylinder 14. The wire 6 ispreferably formed wedgesh'aped or triangular in cross section, havingthe base 16 thereof equal to the altitude and oriented with the base 16extending perpendicular to the flow axis of the stream 4. A strain gauge18 or the like is provided to provide electrical signals indicative ofthe deflection of the yoke 8 caused by impingement of the stream 4 onthe wire 6. The hydraulic cylinder 14 serves to cause the wire 6 totransect the stream 4 and suitable means 20 are connected to the piston12 to provide electrical signals indicating the position of the wire 6.Bafiies 22 formed with apertures 24 are positioned fore and aft of theyoke 8 provide a dead region to prevent spray reaction with the broadportion of the yoke 8. Pressure differential across valve 2 is measuredconventionally by a differential pressure transducer 26 while injectantflow rate through valve 2 is measured by a flow meter 28.

To express the etficiency of an injector valve in converting thepressure head into stream velocity or momentum, a figure of merit, knownas the momentum recovery, has become widely accepted. This is a ratio ofthe actual velocity of the stream to the ideal velocity, 'based onpressure head in the valve under test. From Bernoullis equation, theideal velocity is where AP is the pressure differential across the valveunder test, and p is the mass density of the fluid. To determine theactual velocity, hydraulic cylinder 14 is actuated to move piston 12from its extended position to its retracted position, causing the wire 6to transect the fluid stream 4. As this is done, the signals from straingauge 18 and position indicator 20 are supplied to a suitable recorder30 which plots a curve, as shown at 32 in FIG. 3, displaying the forceof the fluid impinging on the wire 6-, indicated by the signals fromstrain gauge 18, as a function of the position of the wire 6, indicatedby the signals from position indicator 20. It can be shown that theactual stream velocity is V inches second FD 1/2Cnm (II) where F is theintegrated force on the wire 6, C is the drag coefficient of the wire 6and m is the mass rate of particle flow in the stream 4. Since, asstated above, the momentum recovery is the ratio of the actual velocityto the ideal velocity, it is found that the ratio of force representedby the area under curve 32 to the ideal dynamic force of the stream 4 isequal to the product of one half the drag coeflicient of wire 6 timesthe momentum recovery.

When curves showing drag coefficient as a function of Reynolds numberare studied, for various cross sectional configurations of the wire 6,it becomes obvious that the preferred form is a wire having awedge-shaped or triangular cross section oriented with the base of thetriangle presented for impingement by, the stream and extendingperpendicular to the flow axis of the stream 4. It is found that thedrag coeificient of a cylindrical wire varies constantly whereas thecharacteristics of a wire of the preferred configuration are constantfor Reyn- Olds numbers higher than 2000. It is also found that, for dragcoefficient stability, the wire is preferably so dimensioned that thebase of the triangle is equal to its altitude and is less than about 10percent of the maximum expected diameter of the stream 4.

As is well known, the Reynolds number is a ratio of inertia to viscousforces for a fluid acting on a body. However, for Reynolds numbersgreater than 10 it is found that the drag coefl'icient will be afunction of the ratio of the dimensions of the wire 6 and stream 4, asshown in curve 31 of FIG. 4. a

To perform the method of the present invention, the operator firstdetermines the massdensity and viscosity of the injectant fluid andrecords the flow rate, from flow meter 28, and the differentialpressure, from pressure transducer 26. From this information, he cancalculate the ideal thrust and the Reynolds number for the stream 4.Next, he employs the apparatus of the present invention, as describedabove, to obtain a curve similar to curve 32 of FIG. 3. Having donethis, he integrates the area under the curve, as with a compensatingpolar planimeter, and divides the result by the width of the wire 6 todetermine the integrated force on the wire 6. This, added to theinformation noted above, enables the operator to calculate the momentumrecovery of the stream 4 and, hence, the eificiency of the valve 2.

To determine the solidity of the stream 4, the apparatus of the presentinvention is caused to transect the stream 4 at two or more differentdistances from valve 2. This provides two curves corresponding to curves32 and 34 of FIG. 3. The solidity of the stream is defined as theincluded angle between the stream boundaries and stream boundaries aretypically considered to be the points where the curves 32 and 34 are at10 percent of the maximum deflection, as indicated at 36, 38, 40 and 42.To determine the solidity of the stream 4, the points 36, 38, 4t and 42are located on the curves 32 and 34 and straight lines 44 and 46 aredrawn connecting the points on each side, as indicated by lines 44 and46. Thus, the angle 48 included between these lines defines the solidityof the stream 4.

It will be apparent that the stream solidity can be determined byemploying a plurality of the devices of FIG. 1

4 in a tandem arrangement, moreover, made without departing from thepresent invention. Accordingly, it should be clearly understood that theform of the invention described above and shown in the figures of theaccompanying drawings is illustrative only and is not intended to limitthe scope of the invention.

What is claimed is:

1. Apparatus for measuring characteristics of a fluid free stream, saidapparatus comprising:

a wire of wedge-shaped cross-section,

means supporting said wire with the flat side thereof positioned to beimpinged upon by said stream and extending perpendicular to the flowaxis of said stream,

means for causing said wire to transect said stream,

means for indicating the force of fluid impinging ,on

said wire, and

means for indicating the position of said wire.

2. Apparatus for measuring characteristic of a fluid free stream, saidapparatus comprising:

a wire of triangular cross section having the base of said triangleequal to its altitude and positioned for impingement of said stream onsaid base,

means supporting said wire with the base of said triangle extendingperpendicular to the flow axis of said stream,

means for causing said wire to transect said stream,

means for indicating the force of fluid impinging on said wire, and

means for indicating the position of said wire.

3. Apparatus for measuring characteristics of a fluid free stream, saidapparatus comprising:

a wire of triangular cross section having the base of said triangleequal to its altitude,

means supporting said wire with the base of said triangle extendingperpendicular to the flow axis of said stream for impingement of saidstream on said base,

means for causing said wire to transect said stream,

means establishing a first electrical signal indicative of the force offluid impinging on said wire, and

means establishing a second electrical signal indicative of the positionof said wire.

4. Apparatus for measuring characteristics of a fluid free stream, saidapparatus comprising:

a wire of triangular cross section having the base of said triangleequal to its altitude,

means supporting said wire with the base of said triangle extendingperpendicular to the flow axis of said stream to cause said stream toimpinge upon said base,

means for causingsaid wire to transect said stream,

means establishing a first electrical signal indicative of the force offluid impinging on said wire,

means establishing a second electrical signal indicative of the positionof said wire, and

means for recording said first electrical signal as a function of saidsecond electrical signal.

5. Apparatus for measuring characteristics of a fluid free stream, saidapparatus comprising:

a a cylinder,

a piston movable within said cylinder between an extended position and aretracted position,

a piston rod carried by said piston,

a yoke formed on the outer end of said piston rod,

a wire of wedge-shaped cross section secured to the ends of said yokeand oriented with the flat side of said wire extending perpendicular tothe direction of fluid flow to be analyzed,

means for indicating the force of fluid impinging said flat side of saidwire,

means for moving said piston from said extended position to saidretracted position to cause said wire to transect said fluid flow, and

means for indicating the position of said wire.

5 6 6. Apparatus for measuring characteristics of a fluid meansestablishing a second electrical signal indicative free stream, saidapparatus comprising: of the position of said Wire, and

a cylinder, means for recording said first electrical signal as a funcapiston movable Within said cylinder between an extion of said sec-0ndelectrical signal.

tended position and a retracted position, 5 a piston rod carried by saidpiston, References Clted a yoke formed on the outer end of said pistonrod, UNITED STATES PATENTS a Wire of wedge-shaped cross section securedto the 2,380,516 7/1945 Goldberg 73 147 ends of said yoke and orientedwith the flat side of 2 75 591 7 1955 Hagerty et 1 73 said wireextending perpendicular to the direction of fluid flow to be analyzed,10 FOREIGN PATENTS means establishing a first electrical signalindicative of 128,308 7/ 1959 Russiaforce flmd lmPmgmg 531d JAMES J.GILL, Acting Primary Examiner.

means for moving said piston from said extended position to saidretracted position to cause said wire to 15 RICHARD QUEISSERExaminertransect said fluid flow, I. W. MYRACLE, Assistant Examiner.

1. APPARATUS FOR MEASURING CHARACTERISTICS OF A FLUID FREE STREAM, SAIDAPPARATUS COMPRISING: A WIRE OF WEDGE-SHAPED CROSS-SECTION, MEANSSUPPORTING SAID WIRE WITH THE FLAT SIDE THEREOF POSITIONED TO BEIMPINGED UPON SAID STREAM AND EXTENDING PERPENDICULAR TO THE FLOW AXISOF SAID STREAM, MEANS FOR CAUSING SAID WIRE TO TRANSECT SAID STREAM,MEANS FOR INDICATING THE FORCE OF FLUID IMPINGING ON SAID WIRE, ANDMEANS FOR INDICATING THE POSITION OF SAID WIRE.